Formulations with unexpected cleaning performance incorporating a biodegradable chelant

ABSTRACT

A chelating composition suitable for low-temperature use or storage is disclosed. The chelating compositions include 20 to 70 wt. percent of a polar solvent and 30 to 80 wt. percent of a first component of the formula: 
     
       
         
         
             
             
         
       
     
     wherein R is a hydroxyalkyl group and each R′ is individually selected from the group consisting of hydrogen, unsubstituted or inertly substituted alkyl groups, carbonyl-containing alkyl groups, carboxylate-containing alkyl groups, hydroxyalkyl groups and alkoxy groups; R″ is selected from the group consisting of hydrogen, unsubstituted or inertly substituted alkyl groups; carbonyl-substituted alkyl groups, carboxylate-containing alkyl groups, hydroxyalkyl groups and alkoxy groups; M 1  and M 2  are alkali metal ions, wherein the M 1  has a higher atomic weight than M 2 ; wherein x+y=n and the mole fraction of M 1  is greater than 0.70 to 1. Methods of suppressing crystallization and methods of cleaning surfaces employing the compositions described herein are also disclosed.

PRIOR RELATED APPLICATIONS

This application claims benefit of U.S. Provisional No. 60/793,764 filedApr. 21, 2006.

FIELD OF THE INVENTION

Embodiments of the invention are related to cleaning compositions andmethods of cleaning surfaces with the cleaning compositions herein.Particular compositions are suitable for use and/or storage at lowtemperature without substantial crystallization or solidification.

BACKGROUND OF THE INVENTION

Chelants or chelating agents are compounds which formcoordinate-covalent bonds with a metal ion to form chelates. Chelatesare coordination compounds in which a central metal atom is bonded totwo or more other atoms in at least one other molecule or ion, called aligand, such that at least one heterocyclic ring is formed with themetal atom as part of each ring.

Chelating agents for metal ions, such as calcium, magnesium, iron, andmanganese, are desired for a wide range of technical fields. Examples offields of application and end-uses are detergents, in electroplating, inwater treatment, photography, textile industry, paper industry and alsovarious uses in pharmaceuticals, cosmetics, foodstuffs and plantnutrition. Some of these activities may result in the chelating agentsentering the environment. For example, agricultural uses or use indetergents may result in measurable quantities of the chelants in water.

While some chelants are particularly useful for removing metal scaling,they can be susceptible to solidification or crystallization at lowtemperatures. For instance, iminodiacetic acid derivatives are known topossess metal sequestering properties. But concentrated solutions of thedisodium salt of 2-hydroxyethyl iminodiacetic acid, a particularlyuseful derivative of iminodiacetic acid are observed to crystallize, inwhole or in part, in cold weather conditions. Unfortunately, thesolidification is unpredictable and the determining causes ofsolidification have been difficult to ascertain. Consequently, inoperations where the chelant is used in cold climates this random andunpredictable behavior results in undesirably high amounts of chelantthat is unusable at the time it is needed. Thus, it would be useful toprovide chelant compositions that have suppressed solidification orcrystallization at low temperatures.

SUMMARY OF THE INVENTION

Embodiments of the invention describe chelating compositions suitablefor low-temperature use or storage. In other embodiments the inventiondescribes methods of suppressing crystallization of a chelating solutionby employing the compositions described herein. In still otherembodiments, the invention provides a method of cleaning surfaces byproviding cleaning compositions to the surface. The chelatingcompositions and method described herein employ a compositioncomprising:

a) 30 to 80 wt. percent of a first component of the formula:

wherein R is a hydroxyalkyl group having from 1 to about 10 carbonatoms;each R′ is individually selected from the group consisting of hydrogen,unsubstituted or inertly substituted alkyl groups; carbonyl-containingalkyl groups, carboxylate-containing alkyl groups, hydroxyalkyl groupsand alkoxy groups;R″ has from 1 to about 10 carbon atoms and is selected from the groupconsisting of unsubstituted or inertly substituted alkyl groups,carbonyl-substituted alkyl groups, carboxylate-containing alkyl groups,hydroxyalkyl groups and alkoxy groups; or hydrogen;M₁ and M₂ are individually selected from the group consisting of Li+,Na+, K+, and Cs+, preferably K+ and Na+; wherein x+y=n; and the molefraction of M₁ is greater than 0.70 and can be as large as 1, andwherein M₁ has a higher atomic weight than M₂. Some mixtures may containcertain amounts of structures where M₁ and M₂ are equivalent (e.g., somedisodium or dipotassium species may be present); and

b) 20 to 70 wt. percent of a polar solvent; wherein the weightpercentages are based on the total amounts of the first component andthe polar solvent.

In embodiments preferred for some applications, the mole fraction of M₁is less than 1. Particular compositions include a first component wherethe mole fraction of M₁ is about 0.80, about 0.85, about 0.90, about0.95, about 0.99, about 0.995, or less than 1.

Other embodiments of the invention are directed to methods ofsuppressing solidification of a chelating composition. The methodsinclude providing a chelating composition that comprises 20 to 70 wt.percent of a polar solvent and 30 to 80 wt. percent of a first componentas described herein.

Other embodiments of the invention are directed to methods of cleaning asurface. Typically the methods include providing a cleaning compositionthat generally constitutes at least about 0.01 wt. percent of thechelating composition described herein and typically less than about 50wt. percent. Preferably the hard-surface cleaner contains about 0.1 toabout 25 wt. percent of the chelating composition, and more preferablyabout 0.5 to about 15 wt. percent and removing the composition from thesurface.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following description, whenever a numerical range with a lowerlimit, R^(L) and an upper limit, R^(U), is disclosed, any number fallingwithin the range is specifically disclosed. In particular, the followingnumbers within the range are specifically disclosed:R=R^(L)+k*(R^(U)−R^(L)), wherein k is a variable ranging from 1% to 100%with a 1% increment, i.e., k is 1%, 2%, 3%, 4%, 5%, . . . , 50%, 51%,52%, . . . , 95%, 96%, 97%, 98%, 99%, or 100%. Moreover, any numericalrange defined by two R numbers as defined in the above is alsospecifically disclosed.

In one aspect, the invention provides a chelating composition suitablefor low-temperature use or storage. The compositions preferably comprisea) 30 to 80 wt. percent of a first component of the formula:

wherein R is a hydroxyalkyl group having from 1 to about 10 carbon atomsand each R′ is individually selected from the group consisting ofhydrogen, unsubstituted or inertly substituted alkyl groups;carbonyl-containing alkyl groups, carboxylate-containing alkyl groups,hydroxyalkyl groups and alkoxy groups; R″ has from 1 to about 10 carbonatoms and is selected from the group consisting of unsubstituted orinertly substituted alkyl groups, carbonyl-substituted alkyl groups,carboxylate-containing alkyl groups, hydroxyalkyl groups and alkoxygroups; or hydrogen. M₁ and M₂ are individually selected from the groupsconsisting of Li+, Na+, K+, and Cs+, preferably Na+ and K+; x+y=n andthe mole fraction of M₁ is greater than 0.70 to 1, and wherein M₁ has ahigher atomic weight than M₂, more preferably M₁ is K+ and M₂ is Na+.The chelating compositions also include b) 20 to 70 wt. percent of apolar solvent. The weight percentages are based on the total amounts ofthe first component and the polar solvent.

In some embodiments, the compositions comprise about 40 to about 70 wt.percent, 45 to about 55 wt. percent, or about 50 to about 60, wt.percent of the first component. In particular embodiments, the firstcomponent follows the formula (M₁ ⁺)_(x)(M₂⁺)_(y)(HOCH₂CH₂N(CH₂COO)₂)⁻²; wherein x+y=2, referred to hereafter as(M₁ ⁺)_(x)(M₂ ⁺)_(y)(HEIDA). While any combination of M₁ ⁺ and M₂ ⁺ maybe used, M₁ ⁺ is K⁺ and M₂ ⁺ is Na⁺ in preferred embodiments. In someembodiments the mole fraction of M₁ can be about 0.75 to about 0.80,about 0.85, about 0.90, about 0.95, about 0.99, or to 1. Likewise, insome embodiments, the lower limit on the mole fraction of M₁ can beabout 0.80, about 0.85, about 0.90, about 0.95, about 0.99, about 0.995,or 1. In some embodiments, the upper limit of the range may be 0.80,0.85, 0.90, to 0.95. In particular embodiments the mole fraction of M₁ranges from 0.75 to about 0.99, or about 0.80 to 1. In otherembodiments, the mole fraction of M₁ as represented by x ranges from0.85 to about 0.99, or about 0.80 to about 0.90.

Compositions having two different alkali metal ions may be prepared byseparately forming and isolating the different metal salts. For example,Na₂(HEIDA) and K₂(HEIDA) may be separately prepared by hydrolysis withsodium hydroxide and potassium hydroxide, respectively, and thencombined in the desired ratio. Or a mixture of alkali metal hydroxidesmay be used to conduct the hydrolysis in order to provide the desiredratio of alkali metals. For example, in some embodiments, the hydrolysiscan be performed with the desired ratio of sodium hydroxide andpotassium hydroxide thereby forming the K/Na(HEIDA) in a single step toprovide a dimetallic salt of the formula (K)_(x)(Na)_(y)(HEIDA).Whatever alkali addition scheme is used, the final molar ratio of M₁ isgreater than 0.70 in the formula (M₁ ⁺)_(x)(M₂⁺)_(y)(HOCH₂CH₂N(CH₂COO)₂)⁻², and typically the hydrolysis is performedin the presence of an excess molar amount of base at a temperature fromabout 20 to about 105° C.

In other embodiments, the nitrile functionality can be hydrolyzed usingstrong acids such as hydrochloric or sulfuric acid. In this case, theammonium salt of the respective acid is obtained as a by-product.

One method for preparing the compositions described herein entails theaddition of a cyanide source and a reactive aldehyde to ahydroxyalkylamine in the presence of appropriate sources of the desiredalkali metals. The reactive aldehyde and the hydroxyalkylamine areselected to provide the desired R′, R″ and R groups of the firstcomponent. In a preferred method, HCN and formaldehyde are added to2-hydroxyethylamine and alkali metal hydroxide solutions wherein theresulting mole fraction of M₁ ranges from greater than 0.7 to 1 in theformula (M₁)_(x)(M₂)_(y)(HEIDA). Alternatively, glycolonitrile may beused in place of the HCN and formaldehyde. In addition, the compositionsmay be formed by adding the desired alkali metal cyanides andformaldehyde to the hydroxyalkylamine. For example, production ofcompositions comprising (M₁ ⁺)_(x)(M₂ ⁺)_(y)(HOCH₂CH₂N(CH₂COO)₂)⁻² canbe accomplished by adding the desired proportions of alkali metalcyanides and formaldehyde to 2-hydroxyethylamine. The respective alkalimetal hydroxides or alkali metal cyanides may be added independently, asmixtures, or concurrently with other components in the hydrolysisreaction as long as the final molar fraction of M₁ ranges from greaterthan 0.7 to 1 in the formula (M₁ ⁺)_(x)(M₂ ⁺)_(y)(HOCH₂CH₂N(CH₂COO)₂)⁻².The reactants are combined under any suitable reaction conditions.Preferably the reactants are combined at a temperature and pressure toachieve alkaline hydrolysis, thereby rapidly converting the2-hydroxyethylamine to the alkali metal HEIDA composition. Temperaturesranging from about 20° C. to the reflux temperature of the solvent arepreferred. A temperature of at least 60° C. typically provides asuitable reaction rate. Also higher temperatures may drive the reactionby forcing the ammonia by-product out of the reaction mixture Ammoniaremoval may also be facilitated using reduced pressure. When usingmethods comprising the hydrolysis step, a mixture containing(M₁)_(x)(M₂)_(y)(HOCH₂CH₂N(R)(CH₂COO))^(−n) is usually formed wherein Ris predominantly (—CH₂COO) with a portion of R also being hydrogen. Inprocess schemes where the dinitrile precursor of HEIDA is formed,isolated and purified prior to alkaline hydrolysis, the hydrolyzedproduct composition will consist essentially of (M₁)_(x)(M₂)_(y)(HEIDA).

Alternatively, the alkali metal HEIDA may be prepared from the acid formof HEIDA and the appropriate alkali metal hydroxides.

Compositions described herein also include a polar solvent. As mentionedabove the solvent can be present in an amount ranging from about 20 to70 wt. percent, based on the amounts of the solvent and the firstcomponent. Some embodiments include 30 to about 60 wt. percent, 35 toabout 55 wt. percent, or about 40 to about 50 wt. percent of the polarsolvent. Some preferred polar solvents have a boiling point of greaterthan 90° C. Some suitable solvents include water, water-soluble orwater-dispersible organic solvents including alcohols having 2 to about16 carbon atoms, diols, glycol ethers, and mixtures thereof. Inchelating compositions, the preferred solvent is water.

The chelating composition can be made by providing the first componentand the polar solvent by any suitable means. For example, in someembodiments, the first component may be provided as a solid and combinedwith the polar solvent. In other embodiments, the first component may bepresent at one concentration in a polar solvent and then diluted withadditional polar solvent or concentrated by removing the solvent at anelevated temperature, or under reduced pressure, or both at an elevatedtemperature and reduced pressure. In some embodiments, the firstcomponent may be formed in an appropriate amount of the polar solventbefore being subjected to one or more purification steps to obtain thedesired composition without separate additional steps of providing thepolar solvent.

In particular embodiments, such chelating compositions are characterizedby their resistance to solidification at low temperatures, such thatless than about 5 wt. percent of the composition forms solids afterbeing maintained at −12° C. for 12 hours. Preferably, less than about0.1 wt. percent form solids after being maintained at −12° C. for aperiod ranging from about 12 hours to 30 days. Other compositions haveless than 1 wt. percent solids, less than 0.1 wt. percent solids, lessthan 0.01 wt. percent solids or are substantially free of solids afterup to 60 days, up to 90 days, up to 120 days or up to 180 days or morewhen maintained at −12° C. Preferably, the chelating compositions aresubstantially free of solids. Insoluble solids may be determined byvisual inspection or may be quantified by filtration and gravimetricmeasurement at low temperature (to prevent melting of the solids). Themethod used to quantify the amount of solids formed may be anappropriate modification of a standard method for determining solidspresent in a liquid. One particular method is “Standard Methods for theExamination of Water and Wastewater,” prepared and published by theAmerican Public Health Association, American Water Works Association,and Water Environment Federation; 19^(th) Edition 1995; Managing EditorMary Ann H. Franson; Section 2540 “Solids”, where the necessary stepsshould be taken to prevent errors due to thawing, melting, ordissolution of solids. Typically, the presence of solids is indicated bya cloudy or hazy appearance upon visual inspection. Thus, compositionsthat are substantially free of solids lack a hazy or cloudy appearanceafter storage at −12° C. for at least 12 hours.

In another aspect, cleaning compositions are described comprising achelating agent derived from a first component as described above. Insuch embodiments, M₁ preferably has a greater atomic weight than M₂, butin some embodiments, no M₂ is present, thereby effectively providing adipotassium first component, particularly of the formula K₂(HEIDA). Insome embodiments, (M₁)_(x)(M₂)_(y)(HEIDA) wherein M₁ is potassium and M₂is sodium may be more effectively used if compatibility issues arisewith K₂(HEIDA). Compositions wherein the first component comprises(M₁)_(x)(M₂)_(y)(HEIDA) are particularly advantageous for use inhard-surface cleaning applications, such as certain automaticdishwashing agents and kitchen or bathroom soil removal, especiallycalcium soap removal from bathtub surfaces. Some (M₁)_(x)(M₂)_(y)(HEIDA)compositions are advantageous for use in hard-surface cleaners used forcontrolling alkaline-earth metals, particularly calcium, and inpreventing scaling. When used in hard-surface cleaners, the(M₁)_(x)(M₂)_(y)(HEIDA) generally constitutes at least about 0.01 wt.percent of the cleaner and typically less than about 50 wt. percent.Preferably the hard-surface cleaner contains about 0.1 to about 25 wt.percent (M₁)_(x)(M₂)_(y)(HEIDA), and more preferably about 0.5 to about15 wt. percent (M₁)_(x)(M₂)_(y)(HEIDA).

Such cleaning compositions can also include an anionic, nonionic,cationic, or amphoteric surfactant, and mixtures thereof; optionallyincluding a quaternary ammonium surfactant, the total amount of saidsurfactant being present in an effective amount.

For example, surfactants may be present in hard-surface cleaningcompositions and in some embodiments may comprise from about 0.05 toabout 15 wt. percent of the formulation. Preferably, a surfactant ispresent in a concentration that corresponds to from about 2 to about 6percent surfactant. Concentrated liquid compositions preferably containfrom about 6 to about 10 percent surfactant.

Such surface active agents include water-soluble surfactants such assynthetic anionic, nonionic, cationic, amphoteric and zwitterionicsurfactants and mixtures thereof. Exemplary surfactants include thealkyl benzene sulfates and sulfonates, paraffin sulfonates, olefinsulfonates, alkoxylated (especially ethoxylated) alcohols and alkylphenols, amine oxides, sulfonates of fatty acids and of fatty acidesters, and the like, which are known in the detergency art. Preferably,such surfactants contain an alkyl group in about the C₁₀-C₁₈ range.Anionic surfactants are commonly used in the form of their sodium,potassium or triethanolammonium salts. The nonionics advantageouslycontain from about 3 to about 17 ethylene oxide groups per mole ofhydrophobic moiety. Representative cationic surfactants includequaternary ammonium compounds such as ditallow dimethyl ammoniumchloride, and are preferably used in combination with nonionicsurfactants. Preferred in the composition are about C₁₂-C₁₆ alkylbenzene sulfonates, about C₁₂-C₁₈ paraffin-sulfonates and theethoxylated alcohols of the formula RO(CH₂CH₂O)n, with R being a C₁₂-C₁₅alkyl chain and n being a number from 6 to 10, and the ethoxylatedalcohol sulfates of formula RO(CH₂CH₂O)_(n)SO₃M, with R being a C₁₂-C₁₈alkyl chain, n is a number from about 2 to about 8, and M is H or analkali metal ion.

Anionic surfactants are advantageously present at levels from about 0.3percent to about 8 percent of the hard surface cleaning composition.Nonionic surfactants are preferably used at levels between about 0.1percent to about 6 percent by weight of the composition. Mixtures ofsurfactants are also useful.

Typically, at least one water-soluble or dispersible organic solvent isalso included in the cleaning compositions. Suitable solvents have avapor pressure of at least 0.001 mm Hg at 25° C., said at least oneorganic solvent present in a solubilizing- or dispersion-effectiveamount. The solvent is a water soluble or dispersible organic solventhaving a vapor pressure of at least 0.001 mm Hg at 25° C. It ispreferably selected from C₁₋₆ alcohols, C₁₋₆ diols, alkylene glycolethers having up to 24 carbon atoms, and mixtures thereof. Particularlyuseful alcohols include methanol, ethanol, n-propanol, isopropanol,butanol, pentanol, hexanol, their various positional isomers, andmixtures of the foregoing. Particularly suitable diols may includemethylene, ethylene, propylene and butylene glycols, and mixturesthereof.

In some embodiments of the cleaning compositions, an alkylene glycolether solvent may be preferred. The alkylene glycol ether solvents caninclude ethylene glycol monobutyl ether, ethylene glycol monopropylether, propylene glycol n-propyl ether, propylene glycol monobutylether, diethylene glycol n-butyl ether, dipropylene glycol methyl ether,dipropylene glycol N-butyl ether and mixtures thereof. Preferred glycolethers are ethylene glycol monobutyl ether, also known as butoxyethanol,and 2-(2-butoxyethoxy)ethanol, and propylene glycol n-propyl ether, anddipropylene glycol N-butyl ether (DPNB), available from a variety ofsources. Another preferred alkylene glycol ether is propylene glycolt-butyl ether, which is commercially sold as Arcosolv PTB™, by ArcoChemical Company. The n-butyl ether of propylene glycol is alsopreferred. Certain terpene and terpene derivatives, such as, withoutlimitation, d-Limonene, are also suitable for use. If mixtures ofsolvents are used, the amounts and ratios of such solvents used areimportant to determine the optimum cleaning performances of theinventive cleaner. It is preferred to limit the total amount of solventto no more than 50%, more preferably no more than 25%, and mostpreferably, no more than 15%, of the cleaner. A preferred range is about1-15%. These amounts of solvents are generally referred to asdispersion-effective or solubilizing effective amounts, since the othercomponents, such as surfactants, are materials which are assisted intosolution by the solvents. The solvents are also important as cleaningmaterials on their own, helping to loosen and solubilize greasy soilsfor easy removal from the surface cleaned.

Hard-surface cleaning compositions, particularly those containing(M₁)_(x)(M₂)_(y)(HEIDA), may be useful in a wide pH range of about 2 to14. Preferably the pH of the cleaning composition is from about 3 toabout 13, and more preferably from about 4 to about 12.

Other optional ingredients include detergent builders, within the skillin the art, including nitrilotriacetate (NTA), polycarboxylates,citrates, water-soluble phosphates such as tri-polyphosphate and sodiumortho- and pyro-phosphates, silicates, ethylene diamine tetraacetate(EDTA), amino-polyphosphonates, phosphates and mixtures thereof.

Other optional additives for the hard surface cleaners include detergenthydrotropes. Exemplary hydrotropes include urea, monoethanolamine,diethanolamine, triethanolamine and the sodium, potassium, ammonium andalkanol ammonium salts of xylene-, toluene-, ethylbenzene- andisopropyl-benzene sulfonates.

The hard-surface cleaning compositions of the invention also optionallycontain an abrasive material. The abrasive materials includewater-insoluble, non-gritty materials known for their relatively mildabrasive properties. Abrasive materials having a Mohs hardness of nomore than about 7 are preferred; while abrasives having a Mohs hardnessof no more than about 3, are useful to avoid scratches on finishes suchas aluminum or stainless steel. Suitable abrasives include inorganicmaterials, especially such materials as calcium carbonate anddiatomaceous earth, as well as materials such as Fuller's earth,magnesium carbonate, China clay, actapulgite, calcium hydroxyapatite,calcium orthophosphate, dolomite and the like. The aforesaid inorganicmaterials can be described as “strong abrasives”. Organic abrasives suchas urea-formaldehyde, methyl methacrylate melamine-formaldehyde resins,polyethylene spheres and polyvinylchloride are advantageously used toavoid scratching on certain more delicate surfaces, such as plasticsurfaces. Preferred abrasives have a particle size range of about10-1000 microns and are preferably used at concentrations of about 5percent to about 30 wt. percent of the hard surface cleaningcompositions.

Thickeners are preferably used to suspend the abrasives. Levels ofthickener difficult to rinse from the cleaned surfaces are undesirable.Accordingly, the level is preferably less than about 2 percent,preferably from about 0.25 to about 1.5 percent. Exemplary thickenersinclude polyacrylates, xanthan gums, carboxymethyl celluloses, swellablesmectite clay, and the like.

In some embodiments, the cleaning compositions also include water. Otheroptional components of the formulation may include buffers, builders,hydrotropes, grease-cutting agents such as d-limonene, thickeners,antifoaming agents, anti-spotting agents, corrosion inhibitors,anti-oxidants, and others. Soaps, especially soaps prepared from coconutoil fatty acids are also optionally included in the hard surfacecleaners. Such other components, including water, may comprise fromabout from 0.05 to 25 wt. percent of the composition.

Additional optional components include components within the skill inthe art to provide aesthetic or additional product performance benefits.Such components include perfumes, dyes, optical brighteners, soilsuspending agents, detersive enzymes, gel-control agents, thickeners,freeze-thaw stabilizers, bactericides, preservatives, and the like.

Some compositions herein are in the form of creamy scouring cleansers,preferably containing an abrasive material, surface-active agent, andthe (HEIDA) chelating compositions, particularly compositions including(K)_(x)(Na)_(y)(HEIDA), where the mole fraction of M1 ranges fromgreater than about 0.70 to 1, preferably from about 0.75 to 1, or about0.80 to 1. In other embodiments, the mole fraction of M₁ ranges from0.85 to about 0.99, or about 0.80 to about 0.90.

The cleaning compositions can be packaged in a container that comprisesa means for creating a spray, e.g., a pump, aerosol propellant or sprayvalve. The composition can be thus conveniently applied to the surfaceto be cleaned by conventional means, such as wiping with a paper towelor cloth, without the need for rinsing.

In some embodiments of the cleaning compositions, the biodegradablechelant (M₁)_(x)(M₂)_(y)(HEIDA) can be used in hard-surface cleanersfree of organic solvents. This is particularly advantageous in thatcleaning can be done without the concern for release of organic solventinto the environment.

Salts having the formula (M₁)_(x)(M₂)_(y)(HEIDA) may also be used inpipes, vessels, heat exchangers, evaporators, and filters for control ofalkaline-earth and transition metals, particularly calcium and iron, andin preventing scaling. HEIDA and its soluble salts demonstrateadvantages over EDTA due to their enhanced biodegradability and greatersolubility across the pH range. (M₁)_(x)(M₂)_(y)(HEIDA) can be employedin these applications in an amount effective to control alkaline earthand transition metals and prevent scaling in pipes, vessels, heatexchangers, evaporators, and filters. An effective amount of the(M₁)_(x)(M₂)_(y)(HEIDA) employed in these applications may be readilydetermined by a person skilled in the art. The effective amount isdictated by the amount of troublesome metals that need to be controlled.For example, typically, in boiler feed water, HEIDA is used in an amountof from about 1 to about 1000 ppm, preferably from about 1 to about 100ppm, more preferably from about 1 to about 20 ppm. In water systems withhigher levels of hardness and other metal ions, effective amounts ofHEIDA are near or at stoichiometric amounts of metal ion to HEIDA. Thus,when water soluble salts of the formula (M₁)_(x)(M₂)_(y)(HEIDA) areused, they are used in an amount which will provide the aforementionedamounts of HEIDA.

The compositions described herein may be used in a method of cleaning asurface, wherein the method comprises contacting the surface with acleaning composition as described herein and removing the compositionfrom the surface. In some embodiments the (M₁)_(x)(M₂)_(y)(HEIDA)compositions are also useful for cleaning or removing mineral scaledeposits that have accumulated in pipes, vessels, heat exchangers,evaporators, and filters. An effective amount of HEIDA employed in theseapplications can be readily determined by a person skilled in the art.Typically, HEIDA is used in an amount of from about 0.1 to about 50,preferably from about 1 to about 30, more preferably from about 2 toabout 20 percent by weight based on the weight of the aqueous solutionof HEIDA or a salt thereof. For removing scale deposits, the pH of theHEIDA solutions and HEIDA salt solutions comprising(M₁)_(x)(M₂)_(y)(HEIDA) used may be chosen based on the mostadvantageous pH for scale removal and for minimizing corrosion of thesubstrate being cleaned. (M₁)_(x)(M₂)_(y)(HEIDA) may be preferred inthese applications due to its enhanced biodegradability and greatersolubility at effective concentrations over the pH range of about 2 to13. Typically, the temperature of the scale removal process is between10 and 150° C., preferably from about 20 to 120° C., and more preferablyfrom about 30 to 100° C. Again, (M₁)_(x)(M₂)_(y)(HEIDA)-containingcompositions, should be used in an amount which will provide theaforementioned amounts of HEIDA.

Some embodiments of the compositions described herein are alsoadvantageous for use in the oil field applications such as, for example,for drilling, production, recovery, and hydrogen sulfide abatement. Somecompositions demonstrate advantages in these applications over EDTA dueto their enhanced biodegradability and greater solubility across the pHrange. In particular, some of the compositions are useful for control ofalkaline-earth metals, particularly calcium, and in preventing scalingin oil drilling, production and recovery applications. Compositions canalso be employed in the oil field applications in an effective amount tocontrol or prevent scaling. An effective amount of(M₁)_(x)(M₂)_(y)(HEIDA) in the compositions for use in oil fieldapplications can be determined by a person skilled in the art.Typically, HEIDA is used in an amount of from about 0.1 to about 50,preferably from about 1 to about 40, more preferably from about 2 toabout 20 percent by weight based on the weight of the aqueous solution.The water soluble salt of the formula (M₁)_(x)(M₂)_(y)(HEIDA) should beused in an amount which will provide the aforementioned amounts ofHEIDA.

Production fluid from oil wells contains a mixture of oil and water. Thewater usually contains soluble cations, such as, calcium, magnesium andiron in addition to soluble carbonate, bicarbonates, sulfates and otheranions. As this mixture is produced, the pressure of the well can changecausing a shift in equilibrium of the soluble species. For example,calcium can react with carbonate to form calcium carbonate which candeposit on the well perforation and well casing which can limit wellproduction.

Production can be restored by mechanical and chemical removal of thescale deposit. Chemical treatment is often the most effective method forremoving calcium carbonate and calcium sulfate deposits from the wellperforation. Compositions including (M₁)_(x)(M₂)_(y)(HEIDA) compositionsused for removing calcium deposits from the well perforation haveacceptable dissolution performance that in at least some embodiments isequivalent to or better than EDTA. Some compositions comprising(M₁)_(x)(M₂)_(y)(HEIDA) have the added advantage of greater solubilityacross the pH range than EDTA and its respective salts, particularly atpH values of less than about 5.

In other embodiments, compositions comprising (M₁)_(x)(M₂)_(y)(HEIDA)are useful, for instance, in food products vulnerable to metal-catalyzedspoilage or discoloration; in cleaning and laundering products forremoving metal ions, e.g. from hard water that may reduce theeffectiveness, appearance, stability, rinsibility, bleachingeffectiveness, germicidal effectiveness or other property of thecleaning agents; in personal care products like creams, lotions,deodorants and ointments to avoid metal-catalyzed oxidation andrancidity, turbidity, reduced shelf-life and the like; and in pulp andpaper processing to enhance or maintain bleaching effectiveness.Compositions comprising (M₁)_(x)(M₂)_(y)(HEIDA) can also be used inpipes, vessels, heat exchanges, evaporators, filters and the like toavoid or remove scaling; in pharmaceuticals; in metal working; intextile preparation, desizing, scouring, bleaching, dyeing and the like;in agriculture as in chelated micronutrients or herbicides; inpolymerization or stabilization of polymers; in photography, e.g. indevelopers or bleaches; and in the oil field such as for drilling,production, recovery, hydrogen sulfide abatement and the like. Theamount of chelating agent employed in the above noted applications maybe readily determined by one skilled in the art.

EXAMPLES Comparative Examples 1-3

A mixture containing 25 wt. percent Na₂HEIDA is prepared by dilutingNa₂HEIDA with an appropriate amount of water. A laboratory rig isassembled including a stainless steel centrifugal pump, stainless linesand fittings, and a 10-micron filter media using fittings and valves tosimulate plant equipment and procedures. Portions of the composition arehandled at about 10° C., 0° C. and −10° C., respectively and then testedfor crystallization or freezing by being placed in a −12° C. freezer for12 hours. Examination of each of the compositions after being maintainedin the freezer show significant solids formation.

Comparative Examples 4-6

A mixture containing 40 wt. percent Na₂HEIDA is prepared by dilutingNa₂HEIDA with an appropriate amount of water. A laboratory rig isassembled including a stainless steel centrifugal pump, stainless linesand fittings, and a 10-micron filter media using fittings and valves tosimulate plant equipment and procedures. Portions of the composition arehandled at about 10° C., 0° C., and −10° C. and then tested forcrystallization or freezing by being placed in a −12° C. freezer for 12hours. Examination of the composition after being maintained in thefreezer show significant solids formation.

Comparative Examples 7-9

A mixture containing 55 wt. percent Na₂HEIDA is prepared by dilutingNa₂HEIDA with an appropriate amount of water. A laboratory rig isassembled including a stainless steel centrifugal pump, stainless linesand fittings, and a 10-micron filter media using fittings and valves tosimulate plant equipment and procedures. Portions of the composition arehandled at about 10° C., 0° C., and −10° C. When handled at 0° C. and−10° C., the solutions can not be pumped. The 10° C. solution can bepumped in the laboratory rig. The 10° C., 0° C., and −10° C. solutionsare then tested for solids formation by being placed in a −12° C.freezer for 12 hours. Examination of the compositions after beingmaintained in the freezer show significant solids formation.

Comparative Example 10

A composition comprising 25 wt. percent HEIDA species having a formulaof (K)_(1.2)(Na)_(0.8)(HEIDA) is prepared by combining 15.54 wt. percentK₂HEIDA and 9.46 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described in theComparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows significant solids formation.

Comparative Example 11

A composition comprising 25 wt. percent HEIDA species having a formulaof (K)_(1.4)(Na)_(0.6)(HEIDA) is prepared by combining 17.97 wt. percentK₂HEIDA and 7.03 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows significant solids formation.

Comparative Example 12

A composition comprising 25 wt. percent HEIDA species having a formulaof (K)_(1.6)(Na)_(0.4)(HEIDA) is prepared by combining 20.35 wt. percentK₂HEIDA and 4.65 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows significant solids formation.

Comparative Example 13

A composition comprising 25 wt. percent HEIDA species having a formulaof (K)_(1.8)(Na)_(0.2)(HEIDA) is prepared by combining 22.70 wt. percentK₂HEIDA and 2.30 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows significant solids formation.

Comparative Example 14

A composition comprising 25 wt. percent of K₂HEIDA is prepared bycombining 25.0 wt. percent K₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows significant solids formation.

Comparative Example 15

A composition comprising 40 wt. percent HEIDA species having a formulaof (K)_(1.2)(Na)_(0.8)(HEIDA) is prepared by combining 24.86 wt. percentK₂HEIDA and 15.14 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows solids formation.

Comparative Example 16

A composition comprising 40 wt. percent HEIDA species having a formulaof (K)_(1.4)(Na)_(0.6)(HEIDA) is prepared by combining 28.75 wt. percentK₂HEIDA and 11.25 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows solids formation.

Example 17

A composition comprising 40 wt. percent HEIDA species having a formulaof (K)_(1.6)(Na)_(0.4)(HEIDA) is prepared by combining 32.57 wt. percentK₂HEIDA and 7.43 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition did not show solids formation.

Example 18

A composition comprising 40 wt. percent HEIDA species having a formulaof (K)_(1.8)(Na)_(0.2)(HEIDA) is prepared by combining 36.32 wt. percentK₂HEIDA and 3.68 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition did not show solids formation.

Example 19

A composition comprising 40 wt. percent of K₂HEIDA is prepared bycombining 40.0 wt. percent K₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner described above inComparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition did not show solids formation.

Comparative Example 20

A composition comprising 55 wt. percent HEIDA species having a formulaof (K)_(1.2)(Na)_(0.8)(HEIDA) is prepared by combining 34.19 wt. percentK₂HEIDA and 20.81 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner described above inComparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows solids formation.

Comparative Example 21

A composition comprising 55 wt. percent HEIDA species having a formulaof (K)_(1.4)(Na)_(0.6)(HEIDA) is prepared by combining 39.53 wt. percentK₂HEIDA and 15.47 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner described above inComparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows solids formation.

Comparative Example 22

A composition comprising 55 wt. percent HEIDA species having a formulaof (K)_(1.6)(Na)_(0.4)(HEIDA) is prepared by combining 44.78 wt. percentK₂HEIDA and 10.22 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition shows solids formation.

Example 23

A composition comprising 55 wt. percent HEIDA species having a formulaof (K)_(1.8)(Na)_(0.2)(HEIDA) is prepared by combining 49.93 wt. percentK₂HEIDA and 5.07 wt. percent Na₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition did not show solids formation.

Example 24

A composition comprising 55 wt. percent of K₂HEIDA is prepared bycombining 55.0 wt. percent K₂HEIDA with water. The composition ishandled at −10° C. in substantially the same manner as described abovein Comparative Examples 7-9. After storage for 12 hours at −12° C. thecomposition did not show solids formation.

Example 25

A composition comprising about 39-40% HEIDA species wherein theresulting mole fraction of M₁ equals 0.8 in the formula(M₁)_(x)(M₂)_(y)(HOCH₂CH₂N(R)(CH₂COO))^(−n) wherein R is predominately—CH₂COO with a minor portion of R also being hydrogen is prepared asfollows: 61.09 grams of hydroxethylamine and 201.97 grams of 45% KOH,32.88 grams of 50% NaOH, and about 250 grams of deionized water arecombined in a stainless steel reactor. While stirring and heating at atemperature of approximately 100° C., an aqueous glycolonitrile solution(about 285 grams 40% active) is slowly added. Air is sparged into thereaction solution to aid elimination of the by-product ammonia. Water isadded in increments as needed to maintain the proper liquid volume.After completion of the reaction, the solution is cooled and deionizedwater is added to achieve the final concentration of about 39 wt.percent (K)_(1.6)(Na)_(0.4)(HEIDA) and about 1 wt. percent(K)_(0.8)(Na)_(0.2)(HOCH₂CH₂N(H)(CH₂COO). Products incorporating therange of molar ratios wherein the mole fraction of M₁ is greater than0.7 are prepared in a similar manner as above by applying theappropriate amount of the alkali metal source. The alkali metalcomponents may be added separately or as mixtures, added incrementallyor in a continuous fashion as long as the final molar fraction of M₁ isgreater than 0.7 in the formula(M₁)_(x)(M₂)_(y)(HOCH₂CH₂N(R)(CH₂COO))^(−n) wherein R is (—CH₂COO) orhydrogen with R being predominately (—CH₂COO), or R is essentially all(—CH₂COO).

Compositions having 25 wt. percent Na₂HEIDA but substantially lackingK₂HEIDA form solids at −12° C. after 12 hours. Compositions having bothNa₂HEIDA and K₂HEIDA and 25 wt. percent HEIDA species also form solids.Compositions having both Na₂HEIDA and K₂HEIDA and 40 wt. percent HEIDAspecies show acceptable behavior where less than 12 wt. percent,preferably less than 10 wt. percent, or less than 8 wt. percent ofNa₂HEIDA is present. Acceptable behavior is shown for compositionshaving both Na₂HEIDA and K₂HEIDA and 55 wt. percent HEIDA species, whenless than 10 wt. percent, preferably less than 9 wt. percent, less than8 wt. percent, or less than 6 wt. percent Na₂HEIDA is present.

Some of the compositions having 40 wt. percent and 55 wt. percentK₂HEIDA provide acceptable cold weather handling and storage performancewhile compositions having 25 wt. percent K₂HEIDA have solids present at−12° C. after about 12 hours.

Cleaning formulations are prepared to contain the following (by weight):2.62% Sodium dodecylbenzene sulfonic acid, 2.62% cocoamidopropyl betaine(Lonzaine C), 2.62% ethylene glycol butyl ether (Dowanol EB™), 3.2% ofthe chelant salt (except for the blank, which contains all componentsexcept the chelant), and the balance water. Thus the formulation ofExample 31 contains 3.2% by weight of the chelant salt (in this case,K₂HEIDA), and so on for Examples 32 and 33 which evaluate(K)_(1.8)(Na)_(0.2)(HEIDA), and (K)_(1.6)(Na)_(0.4)(HEIDA),respectively, as well as Comparative Examples 27-30 which evaluate theformulations containing Na₄EDTA, Na₂HEIDA, K₄EDTA, and(K)_(1.0)(Na)_(1.0)(HEIDA), respectively.

The cleaning ability of these compositions is determined according toASTM D5343, “Standard Guide for Evaluating Cleaning Performance ofCeramic Tile Cleaners:” using soiled white bathroom tiles as directed bythe procedure. The principal metal-containing components of the soilmixture are calcium, magnesium, and ferric iron, present as their highlyinsoluble stearate salts (soap scum). The soiled tiles are placed in thescrubbing apparatus. 10 ml of the cleaning formulation is placed on theface of a pre-moistened sponge, then the number of strokes (under 454grams of force) are determined to achieve soil removal of 90% orgreater. The number of strokes required by each formulation to obtain90% or greater soil removal is recorded for each cleaning formulation.Results are in the Table 1 below:

TABLE 1 Chelant in Number of Example formulation Strokes Comparative 26none >80 Comparative Example 27 Na₄EDTA >80 Comparative Example 28Na₂HEIDA >80 Comparative Example 29 K₂EDTA 19 (+/−2) Comparative Example30 (K)_(1.0)(Na)_(1.0)(HEIDA) 80 (+/−2) Example 31(K)_(2.0)(Na)_(0.0)HEIDA 19 (+/−2) Example 32 (K)_(1.8)(Na)_(0.2)(HEIDA)19 (+/−2) Example 33 (K)_(1.6)(Na)_(0.4)(HEIDA) 18 (+/−2)

These results indicate that cleaning with the claimed(K)_(x)(Na)_(y)(HEIDA) compositions where the mole fraction of M₁ isgreater than 0.70, is substantially the same as cleaning with the K₄EDTAformula and better than cleaning compositions containing the Na₄EDTAformula, even though the (K)_(x)(Na)_(y) (HEIDA) is a much weakerchelant for Ca²⁺, Mg²⁺, and Fe³⁺ ion than either K₄EDTA or Na₄EDTA. Theresults also indicate that cleaning with the claimed(K)_(x)(Na)_(y)(HEIDA) formulations is better than cleaning with theNa₂HEIDA formulation.

To compare the strength of various chelating agents, their metal bindingconstants are determined in the laboratory by techniques such asdescribed in Determination and Use of Stability Constants by A. E.Martell and R. J. Motekaitis. Table 2 below lists the stabilityconstants of HEIDA and EDTA with calcium, magnesium, and ferric iron.The values are logarithmic, thus each unit represents an order ofmagnitude. Therefore, a difference of one Log K unit represents a factorof 10 in binding strength, while two units represent a factor of 100,etc. Values reported below are the overall constants as compiled in the“NIST Critical Stability Constants of Metal Complexes Database,”expressed as the log of the concentration of the metal complex dividedby the product of the concentration of the free metal and free ligand.

TABLE 2 Chelant Log K Ca Log K Mg Log K Fe3+ EDTA 10.7 8.7 25.1 HEIDA4.7 3.4 11.6

The above Log K values show the dramatically greater chelation strengthof EDTA as compared to HEIDA. One would expect that the chelating agentwith the greatest metal ion affinity (in this case, EDTA) would have thebetter performance for removing the soil containing Ca, Mg, and Fe3+.Unexpectedly, in the ASTM tile cleaning test, K₂HEIDA demonstrates equalperformance to the much stronger chelating agent, K₄EDTA. K₂HEIDA hasthe advantage of being readily biodegradable in standard laboratorybiodegradation tests including, among others, OECD 301A, OECD 301B, OECD301D, OECD 301E, and the very stringent OECD 306 seawater biodegradationtest.

The primary metal present in the standard ASTM soil is calcium. Onemethod of estimating the calcium control performance of a chelatingagent is to perform a calcium titration that utilizes the tendency toproduce a calcium precipitate when a given amount of chelant can nolonger control any additional added calcium, thus producing a visibleprecipitate. Using such a titration test, one normally deems the bestchelants for calcium control as those that accept the most calciumbefore the precipitate appears per a given unit of chelating agent. Astandard titration test often employed to determine a chelant's calciumcontrol effectiveness is the calcium oxalate titration. In thistitration, standard calcium chloride titrant is added to a measuredamount of chelating agent and the onset of calcium oxalate precipitate(detected as the first permanent turbidity that forms) defines theamount of calcium that can be controlled. Strong chelants accept amole-for-mole amount of calcium, while weaker chelants will accept lessthan a mole-for-mole amount of calcium in this titration.

The calcium oxalate titration is performed by weighing about 5millimoles of the active chelant to a titration vessel, adding water toabout 50 ml total volume, adding 10 ml 3% ammonium oxalate solution,adjusting the pH to about 11.6 with potassium hydroxide solution, andtitrating the sample mixture with standardized 0.5 M CaCl₂ to the firstfaint permanent turbidity. Results are summarized in Table 3 below:

TABLE 3 % Molar Chelation of calcium Chelant (max. = 100) EDTA 100%HEIDA  35%

The calcium oxalate titration data above predicts that K₄EDTA shouldperform much better than K₂HEIDA for the control of calcium. However,the tile cleaning data from ASTM D5343 unexpectedly show that K₂HEIDAperforms equally as well as K₄EDTA.

Example 34

Black ceramic tiles (meeting ANSI standard A371.1, 4¼″ square) aresoiled as directed by the procedure described in Consumer SpecialtiesManufacturers Association DCC-16, (CSMA Detergents Division Test MethodsCompendium—Third Edition—May 1995—Pages I-51 to I-55) “Guidelines forEvaluating the Efficacy of Bathroom Cleaners, Part 2: Scrubber Test forMeasuring the Removal of Lime Soap.”. The principal metals present inthe soil mixture used in the tile cleaning test are calcium, followed bymagnesium, present as their highly insoluble stearate salts (soap scum).Cleaning solution formulations are prepared as described in the previousexample. To the surface of the soiled tiles on the scrubbing apparatus,1 gram of cleaning solution is sprayed and allowed to stand for 30seconds. The tile is then scrubbed with a pre-moistened sponge with 454grams of force for 6 cycles (total of 12 passes over the soiled tile).The tile is then rinsed with water and allowed to air dry. Panelistsjudge the cleanliness of the tiles on a scale from 0 to 5 (with “0” forcompletely dirty and “5” for completely cleaned), and the results of theobservations are averaged. Results are in Table 4 below:

TABLE 4 Cleaning rating Chelant in formulation (higher is better) Blank(no chelant) 3.13 (+/−0.14) K4EDTA 3.60 (+/−0.13)(K)_(2.0)(Na)_(0.0)HEIDA 4.67 (+/−0.26) (K)_(1.6)(Na)_(0.4)(HEIDA) 4.59(+/−0.38)

As shown by the data in Tables 2 and 3, it is unexpected that a weakerchelant such as (K)_(x)(Na)_(y)(HEIDA)⁻² would be able to perform aswell as a strong chelant such as K₄EDTA. However, the results in Table 4unexpectedly show that claimed compositions of (K)_(x)(Na)_(y)(HEIDA)⁻²are actually superior to K₄EDTA.

While the invention has been described with a limited number ofembodiments, these specific embodiments are not intended to limit thescope of the invention as otherwise described and claimed herein.Variations and modifications therefrom exist. For example, variousadditives, not enumerated herein, may also be used to further enhanceone or more properties of the compositions described herein. In otherembodiments, the compositions do not include, or are essentially freeof, any components not enumerated herein. As used herein the term“essentially free of” means that such components are not present in morethan trace amounts or are not purposely added to the composition. Also,compositions that consist of or consist essentially of the describedcomponents should be considered as disclosed herein. Typically, whilethe processes are described as comprising one or more steps, it shouldbe understood that these steps may be practiced in any order or sequenceunless otherwise indicated. These steps may be combined or separated.

It should also be noted that compounds and compositions described hereinare in some cases described as ionic salts for convenience only. Suchcompounds and compositions need not actually contain the component ionsin their ionic form in the claimed compositions and processes. And therecited component ions need not be most accurately described asassociated with each other. Rather, the ions of the components may alsoor alternatively be present or described as being associated with otherspecies in the compositions. Compositions and processes wherein theconcentrations of the individual ions are present and could be describedor written in the manner used herein should be considered to be withinthe literal scope of the claimed invention.

Finally, the claimed compositions are not limited to the processesdescribed herein. They can be prepared by any suitable process. Theappended claims intend to cover all such variations and modifications asfalling within the scope of the invention.

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 13. An aqueous hard surface cleaningcomposition, comprising: (a) an anionic, nonionic, cationic, oramphoteric surfactant, and mixtures thereof; optionally including aquaternary ammonium surfactant, the total amount of said surfactantbeing present in an effective amount; (b) at least one water-soluble ordispersible organic solvent having a vapor pressure of at least 0.001 mmHg at 25° C., said at least one organic solvent present in asolubilizing- or dispersion-effective amount; (c) a chelating agentderived from one or more components of the formula:

wherein R is a hydroxyalkyl group having from 1 to about 10 carbonatoms; each R′ is individually selected from the group consisting ofhydrogen, unsubstituted or inertly substituted alkyl groups;carbonyl-containing alkyl groups, carboxylate-containing alkyl groups,hydroxyalkyl groups and alkoxy groups; R″ has from 1 to about 10 carbonatoms and is selected from the group consisting of unsubstituted orinertly substituted alkyl groups; carbonyl-substituted alkyl groups,carboxylate-containing alkyl groups, hydroxyalkyl groups and alkoxygroups; or hydrogen; M₁ and M₂ are individually selected from the groupsconsisting of Na⁺ and K⁺, wherein the M₁ has a higher atomic weight thanM₂; wherein x+y=n and the mole fraction of M₁ is greater than 0.70 to 1;and (d) water.
 14. The cleaning composition of claim 13, wherein the onecomponent of the chelating agent follows the formula(K⁺)_(x)(Na⁺)_(y)(HOCH₂CH₂N(CH₂COO)₂)⁻²; wherein the mole fraction of K⁺ranges from greater than 0.80 to 1, x+y=2, and wherein the pH of thecleaning composition is from about 3 to
 14. 15. The cleaning compositionof claim 14 further comprising an additional component of the chelatingagent of the formula (K⁺)_(x)(Na₂ ⁺)_(y)(HOCH₂CH₂N(R)(CH₂COO))⁻¹ where(R) is hydrogen and wherein the mole fraction of K⁺ ranges from greaterthan 0.80 to 1, wherein x+y=1.
 16. A method of cleaning a surfacecomprising (a) contacting a surface with the cleaning composition ofclaim 13 and (b) removing the composition from the surface.